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[142.167.56.70]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7d09a195d7dsm1046378985a.78.2025.06.04.08.14.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Jun 2025 08:14:33 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1uMpp2-000000006MV-3s6s; Wed, 04 Jun 2025 12:14:32 -0300 Date: Wed, 4 Jun 2025 12:14:32 -0300 From: Jason Gunthorpe To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , John Hubbard , Peter Xu Subject: Re: [PATCH v1] mm/gup: remove (VM_)BUG_ONs Message-ID: <20250604151432.GC17991@ziepe.ca> References: <20250604140544.688711-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250604140544.688711-1-david@redhat.com> On Wed, Jun 04, 2025 at 04:05:44PM +0200, David Hildenbrand wrote: > Especially once we hit one of the assertions in > sanity_check_pinned_pages(), observing follow-up assertions failing > in other code can give good clues about what went wrong, so use > VM_WARN_ON_ONCE instead. > > While at it, let's just convert all VM_BUG_ON to VM_WARN_ON_ONCE as > well. Add one comment for the pfn_valid() check. > > We have to introduce VM_WARN_ON_ONCE_VMA() to make that fly. I'm fine with this, but IMHO, using ON_ONCE is wasteful here. They have been BUG_ONs for ages, they really do never happen. If there was ever a case to justify not using ON_ONCE this is it.. Jason